[Dovecot] Plugin when downloading mail

[martijn at youngguns.nl]

Is there a way to modify mail messages when they are downloaded using a
special login.

eg. my normal login for dovecot is martijn at youngguns.nl but when I log in
using martijn at dosomething.youngguns.nl I would like to download my mail
which are processed using a Perl script. The Perl script will modify the
content of the message (the message body). So I don't want to change the
header or IMAP flags.

Martijn